DEFINING AND
COLLECTING DATA
,OBJECTIVES…
• Understanding issues arise when
defining variables
• How to define variable
• How to collect data
• Identify different ways to collect a
sample
• Understand types of survey error
, Populations vs samples
Population consists of all
Sample is a portion of
the items or individuals
population selected fo
about which you want to
analysis. When you analy
reach conclusion. When
data from sample you
you analyze population you
compute statistics.
compute parameters.
, Collecting Data Via Sampling Is Used
When Selecting A Sample Is
Less time consuming than selecting Less costly than selecting every item Less cumbersome and more practi
every item in the population. in the population. than analyzing the entire populatio